﻿#include "Date.h"

bool Date::CheckDate()
{
	if (_month < 1 || _month > 12 || _day < 1 || _day > GetMonthDay(_year,_month))
	{
		return false;
	}
	else
	{
		return true;
	}
}
Date::Date(int year, int month, int day)
{
	_year = year;
	_month = month;
	_day = day;
	
	if (!CheckDate())
	{
		cout << "输入的日期非法" << endl;
	}
}
void Date::Print() const
{
	cout << _year << "/" << _month << "/" << _day << endl;
}


//运算符重载
//d1 < d2
bool Date::operator<(const Date& d) const
{
	if (_year < d._year)
	{
		return true;
	}
	else if (_year == d._year)
	{
		if (_month < d._month)
		{
			return true;
		}
		else if (_month == d._month)
		{
			return _day < d._day;
		}
	}
	return false;
}
//d1 <= d2
bool Date::operator<=(const Date& d) const
{
	return *this < d || *this == d;
}
//d1 > d2
bool Date::operator>(const Date& d) const
{
	return !(*this <= d);
}
//d1 >= d2
bool Date::operator>=(const Date& d) const
{
	return !(*this < d);
}
//d1 == d2
bool Date::operator==(const Date& d) const
{
	return _year == d._year && _month == d._month && _day == d._day;
}
//d1 != d2
bool Date::operator!=(const Date& d) const
{
	return !(*this == d);
}
//d += 天数
Date& Date::operator+=(int day)
{
	if (_day < 0)
	{
		return *this -= -day;
	}
	
	_day += day;
	while (_day > GetMonthDay(_year, _month))
	{
		_day -= GetMonthDay(_year, _month);
		++_month;
		if (_month > 12)
		{
			++_year;
			_month = 1;
		}
	}

	return *this;
}
//d + 天数
Date Date::operator+(int day) const
{
	Date tmp = *this;
	tmp += day;
	return tmp;
}
//d -= 天数
Date& Date::operator-=(int day)
{
	if (day < 0)
	{
		return *this += -day;
	}

	_day -= day;
	while (_day <= 0)
	{
		--_month;
		if (_month == 0)
		{
			--_year;
			_month = 12;
		}
		_day += GetMonthDay(_year, _month);
	}

	return *this;
}
//d - 天数
Date Date::operator-(int day) const
{
	Date tmp = *this;
	tmp -= day;

	return tmp;
}
//d1 - d2
int Date::operator-(const Date& d) const
{
	Date max = *this;
	Date min = d;
	int flag = 1;
	if (*this < d)
	{
		max = d;
		min = *this;
		flag = -1;
	}

	int n = 0;
	while (min != max)
	{
		--max;
		++n;
	}

	return n * flag;
}
//++d
Date& Date::operator++()
{
	*this += 1;
	return *this;
}
// d1++ -> d1.operator++(0)
// 为了区分，构成重载，给后置++，强行增加了一个int形参
// 这里不需要写形参名，因为接收值是多少不重要，也不需要用
// 这个参数仅仅是为了跟前置++构成重载区分
Date Date::operator++(int)
{
	Date tmp = *this;
	tmp += 1;

	return tmp;
}
//--
Date& Date::operator--()
{
	*this -= 1;
	return *this;
}
Date Date::operator--(int)
{
	Date tmp = *this;
	tmp -= 1;

	return tmp;
}

// 重载
ostream& operator<<(ostream& out, const Date& d)
{
	out << d._year << '/' << d._month << '/' << d._day << endl;
	return out;
}
istream& operator>>(istream& in, Date& d)
{
	in >> d._year >> d._month >> d._day;
	if (!d.CheckDate())
	{
		cout << "输入日期非法" << endl;
	}
	return in;
}
